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Research Project: Conservation, Characterization, and Evaluation of Plant Genetic Resources and Associated Information

Location: Plant Genetic Resources Conservation Unit

Title: Phenotypic characterization of sixteen accessions of sunn hemp (Crotalaria juncea L.)in Florida

item Cho, A - University Of Florida
item Chase, C - University Of Florida
item Koenig, R - University Of Florida
item Treadwell, D - University Of Florida
item Gaskins, J - University Of Florida
item Morris, John - Brad
item Morales-payan, J - University Of Puerto Rico

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2016
Publication Date: 6/22/2016
Citation: Cho, A.H., Chase, C.A., Koenig, R.L., Treadwell, D.D., Gaskins, J., Morris, J.B., Morales-Payan, J.P. 2016. Phenotypic characterization of sixteen accessions of sunn hemp (Crotalaria juncea L.)in Florida. Agronomy Journal. doi: 10.2134/agronj2015.0531.

Interpretive Summary: Sunn hemp is a legume used for fiber, cover cropping, and as a green manure crop for soil improvement. Sixteen sunn hemp accessions were evaluated for biomass, flowering, and reproduction in Florida. The sunn hemp accessions separated into 2 groups based on biomass, large leaf area, flowering and seed production. Sunn hemp accessions could be used as parents in the development of new cultivars for use as sustainable cover crops in the southern U.S.

Technical Abstract: Sunn hemp (Crotalaria juncea L.) is a leguminous cover crop that provides benefits to a cropping system including nitrogen accumulation, weed suppression and soil stability. Adoption of sunn hemp as a cover crop is limited primarily due to the availability of seed sources, leading to high seed costs and unreliable supplies. The photoperiod sensitivity of the commercial cultivar of sunn hemp, ‘Tropic sun’ is a major limiting factor for seed production locations. This experiment was designed to evaluate 16 accessions of sunn hemp for potential commercial seed production in Florida. These accessions were evaluated at three planting dates (May, June, July) for phenotypic characteristics that would provide a baseline for future work to develop a cultivar of sunn hemp that could produce seed in Florida while maintaining desirable cover crop characteristics. It was observed that the accessions separated into two groups of sunn hemp; one with cover crop characteristics (biomass production, large leaf area) while the second group displayed seed production characteristics (photoperiod insensitive, flowering, seedpod production). This work demonstrates the potential to improve these accessions that are photoperiod insensitive for sunn hemp seed production in the continental United States to encourage use of sunn hemp as a cover crop.